A wideband and wide-beam circularly polarized antenna comprises a ground plane, a grooving frustum, a coaxial cable and four butterfly-shaped radiation sheets, wherein the grooving frustum is wide in a bottom part and narrow in a top part and is arranged on the ground plane, the coaxial cable penetrates through a central line of the grooving frustum and is provided with four coaxial lines, and the four butterfly-shaped radiation sheets are respectively connected with inner cores of the four coaxial lines and are symmetrically arranged. Feeding is directly performed by the inner cores of the four coaxial lines, and phases are sequentially different to one another by 90 degrees. By the wideband and wide-beam circularly polarized antenna, the antenna structure can be simplified, and the antenna performance also can be improved.